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So I have a pair of K03's sittin in my room out of a S4... as it is ridiculous how well they fit the M20 engine (number wise)... also theres a PnP megasquirt in the mail somewhere, and injectors out there waiting for me to buy them ... but my question is, do I make a collector (I have a tig welder) and have a single 3in exhaust, or go with twin pipes? I can do the math and twin will add more back pressure as theres more firction goin on there, but having a cat/baffold muffler will prob make the minor losses negligable...right?? any suggestions? some dyno results? ancient wisdom?

And I wont use the stock one as it should prob be somethin a lil bigger/lighter/not rusting/not clamped together if I go dual

Anyone have some sweet clips of their turbo cars exhaust?(I went to youtube just curious if there are any more out there) a nice deep grumble would be nice...which will prob add back pressure

I was also curious about trying to replicate a flowmaster and see how it goes... thoughts?

I think there are a few other guys who've done the twin turbo setup, two of them never completed. If I were doing it, I'd use the already present manifolds and exhaust them into two 2" pipes. You could run two metal substrate cats (they're "thin" and would fit staggered in the factory location no problem) and then into a muffler setup. For mufflers, you can safely go into a collector of say 3" and not lose any performance, as the exhaust gases have cool enough.

Alternatively, you could go with two separate mufflers, a true twin exhaust, even going so far to modify the valance to exit one on each side. That would look swell.

Making a collector isn't hard if you have a bandsaw or are really careful with a hacksaw. You essentially cut two pipes on angles, then once they're positioned together, find the point on the merged area in which the two make a smooth oval and cut the whole thing off flush. Then get larger pipe, hammer it down to make the oval and weld that on.

The angles, oval size and diameter of the larger pipe are the variables in the equation. I know there is some hot math to figure it out (or use Solidworks if you're smart, i'm not) or trial and error. Pipe is cheap, I'd go with the latter.

I'm definately gonna make new manifolds as that's the most significant part to reduce lag and increase power. Also the front manifold will curl up while the rear one goes down. I got 50% of the parts so not much farther to go.

I got no prob makin a collector, and I got all the equations from my school books, so no probs there, although I did forget to take intto account the gases cooling ... And solidworks FTW cause you can print off the profile to cut

I have made a dual exhaust from the cat back independent to the rear valance. Battery removed and put in the middle between strut tower's. I also was thing about two small turbo's as well on the M # 20. Not started yet